1. Field of the Invention
The present invention relates to a home theater system, and more particularly, to a method and apparatus for automatically determining a characteristic of a speaker and automatically setting a speaker mode in an audio/video system.
2. Description of the Related Art
Commonly, a home theater system includes a 5.1 channel amplifier, a digital versatile disc (DVD) playback device, and a tuner, and is used with a large screen digital TV. Also, the home theater system can not only realize high image quality by adopting a progressive scanning function, which is an up-to-date image technology, but can also reproduce 2-channel stereo sound signals from, for example, a video cassette recorder (VCR) or a TV broadcastast, as 5.1 channel sound, using Dolby pro-logic decoding technology.
In such a home theater system, a user should manually set speaker modes based on the number of speakers and reproducing frequency bands of the speakers.
FIG. 1 is a signaling diagram of a conventional digital signal processor for setting speaker modes in a conventional 5.1 channel speaker system.
Referring to FIG. 1, input audio signals of 5.1 channels, such as front, center, surround, surround back, and low frequency effect (LFE) channels, are output to corresponding speakers, respectively. Here, the user sets speaker modes by selecting keys mounted on a remote control or a front panel. The speaker modes are “large”, “small”, and “none”, and the user directly selects one of these speaker modes based on types of the speakers and the number of the speakers. In the “large” speaker mode, all of audio signals in an acoustic frequency band (20 Hz to 20 KHz) are output. In the “small” speaker mode, signals in a mid-to-high frequency band are output, and signals in a low frequency band are output separately to a subwoofer or another speaker. In the “none” speaker mode, no signal is output.
Thus, when speaker modes are set according to user selection, the digital signal processor first determines whether to pass signals through low pass filters (LPFs) or through high pass filters (HPFs) and how to combine the signals, based on the set speaker modes, then processes sound output from a sound reproducer to correspond with each speaker mode, and outputs the processed sound to corresponding speakers.
However, since the user is responsible for setting speaker modes in this conventional speaker mode setting method, it is difficult to operate a plurality of speakers, and it is troublesome to separately determine the settings of the plurality of speakers. Also, since the setting of speaker modes is dependent upon a user's familiarity with the characteristics of the speakers, there is a high possibility of inaccurately setting the reproducible frequency range of speakers. Accordingly, it is difficult to obtain an optimal sound effect. Also, if the speaker mode of large or small includes an unconnected speaker, the listener will not be able to hear sounds that are designated to be played by the unconnected speaker.